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No. 76,845. PATENTED APR. 14; 1868.-

- 0. M. STILLMAN.

COMBINED STEAM GENERATOR AND AIR HEATER.

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O. M. STILL-MAN, OF WESTERLY, RHODE ISLAND.

Letters Patent No. 76,845, dated April 14, 1868.

I IMPROVEMENT COMBINED STEAM-GENERATOR AND AIR-HEATER.

TO ALL WHOM IT MAY CONCERN? Be it'known that I, O M. STILLMAX, of Westerly, in the county of Washington, and State of Rhode Island, have invented certain new and useful Improvements in Combined Steanrand Air-Engines; and I do hereby declare that the following specification, taken in connection with the drawing making a part of thcsame, is a full, clear, and exact description thereof.

The drawing represents the apparatus as out by a plane through the central vertical artis.

-'l'he invention relates to that class of apparatus for developing motive-power in whichboth the force of steam and that of the gases evolved during the process of generating it are combined.

the drawing, 'A represents the outer shell of a boiler, which should be of sufi'ioicnt strength and of proper mat' 'erial to sustain the pressure which, under working conditions, as hereinafter explained, it will be called upon to bear/ 1 My improvement inyolves the use of more than one water-compartment orboiler, and, in the present-instance, two are shown. The first, or, as I may termit, the primarysteam-generator,-B, is cylindrical in form, and extends in height to the conical crown-sheet a b b c, which surmounts it. Within this primary generator, and having its shell concentric with the shell of the generator, is the furnace C, the material andconstruction ofwhich should be adequate to sustain the pressure to which it is xpose-d. The space between the upright walls of the furnace and the shell of the boiler is occupied with water, the height ofwhich body-of water above the dome of the fur nace is maintained at the proper level, by means of a forcing-pump, in the usual way.

I prefer to make use of a single feeding-aperture, for the introduction of fuel to the furnace, which is not shown in the drawing, but it may be located at any convenient point, and should be furnished with a steam-tight door, and a. partition of boiler-plate should surround it, as in the case of similar apertures'through the waterleg of a. locomotive-boiler. I v v Wherever I employ a single feeding=aperture, I construct the grate so that it, with its body of coals, can

I be revolved, whereby any portion of the grate-surface can be brought within the reach of the fireman.

As seen in the drawing, the grate is made'up 0t. bars radiating from a common centre, and surrounded, at the outer ends, by a circular high rim or-fender, 1-. 'The bars are arranged so as to forms. conical figure, the

apex of which is supportedby a central spindle, cl, whose foot is stepped in a bearing, E. A toothed wheeLf,

worked by a crank, g, from the outside, engages with the teeth of a rack, surrounding the under surfaceof the rim of the grate, and a flanch, h, projectingfrom the fender, overlaps a lip riveted to the shell of the firebox,

- which lip may be furnished with friction-rollers.

I It is quite evident that the coals will be kept open the grate-bars by the circular fender i, and that the whole fire-pan so formed can be revolved at will. I

The advantage which results from the conical arrangementvof the grate-bars is, that as the atmospheric air and steam to support combustion are,'as will hereafter be seen, admitted through a close pipe, the axis of which is coincident n'ith the axis of the'cone formedby the gra'te-bars,'the air and steam so admitted will naturally be deflected by the central plate, forming the apex of the cone, and be distributed equally to all parts of the lire. I i v t I From the apex of the crown-sneet of-the furnace rises a flue-pipe, D. Its upper end is furnished with a wiregauze spark-arrester, and above its outlet is a valve, j, which, whenopened, upon starting the fire, allows free passage for all smolrc and products of combustion to escape from the furnace;

Before describing the secondary generator, E, whose location is directly over the primary one, B, and

explainingthe office which it performs, I will trace the direction which the steam from the primary generator takes, after it has been formed, up to the point when itenters the furnace totcombine with the gases evolved by combustion, and from thence trace the course of such combined steam and gases to thepoint of their admis- To assist the explanation,I have designated steamby arrows in blue, and gases byarro ws inreiLand when both agents are combined, I have placed arrows of both colors in near proximity to each other;

aw 2 to Starting, now, with the supposition, that the apparatusis-u'ndcr proper working conditions, the valve 3' bein closed so as to secure the utilization of the gases, as hereinafeer to be eic'phined',-steam, nail; is formed i.r th dz primary generator, will rise, as shown by'the single arrow in blue, and, passing over the circulating-plate I:'- intended, in part, for theprotectionofthe fine-pipe D against overheating invcase the water falls below the properlinc-enter the passage F, which is concentric with the fiuc-pipe, and from thence pass on through the ppe G to the point of distribution. a

I As the volume of steam enters from the pipe G into'the upright side-pipc H, it is free to divide. -The por V tlon which we will now trace descends the side-pipe, and, entering the horizontal pipe I, underneath the furnace,

gainsadmission, through the upright inductionpipe If, to the space within the furnace,-

Accompanying the introduction of such volume'of steam into the-fire-ehamber there is a volume of atmospheric air mired with it, (indicated by dotted light red arrows) which theforce of the steam, in entering .the pipe I, through a contracted enclosed passage, as shown, acting in combination with a self-operating val vcyl", is takenin, in the way explained in the Letters Patent grantcdto me, Augustfl, 185-14 I l ,llhe steam, thus admitted to the furnace, becomes at once decomposed, and its elements, combining with the gases evolved bycombustion, constitute an agent of force which, upon the drawing, is indicated by double arrows-'-on'e in blue, and the other in red. Following the course of this agentor combination of gaseouiforces, it will be seen that it passes up" the ilue-pipc D, aml disch'arging through the gauze bonnet-J, pours itself through the contracted enclosed passages in into the space K, arranged concentrically withthe space F, and, passing through such space, finds admission into the secondary generator E. Contemporaneously with-its entrance into the space K, a volume of simple steam, (si'ngleb'lue arrow) fronrthe primary generator, combines'with it, and gives it impulse, such steam being admitted through the nozzles n'n, opening froin the annular chamber L, which is connected, by the horizontal pipe L',with the side-pipeH, which side-pipe is, as heretofore explained,

in direct communication with the primary generator.

The number of nozzlcs, n, for dischargingjets of'steam into thepa'ssagc K, and the number of contracted orifices, m, into which the nozzles, respectively, enter, should'be as great as the space at hand will afioid. In addition tothe oillce whieh thesejcts of steam perform, in. dragging the-gaseous products of the furnace into the passage K, thcy also incidentally cause a vacuum to be formed in the fluc pipe D, so that, whenever it is desired to charge the furnace with coal-by first closing the stop-cocks, which allgw steam or mixed steam and gases to enter below thc fire-pan-the full volume of the steam from the prim'arygenerator will be discharged thro'ngh'its noz-zles, n and thereby the pressure on the furnace will be immediately relieved, so that thefu rnacedoor can be opened with safetyand convenience. I I

The secondary generator, E, is located directly above the primary one, Its'bott'om isseparated'from the crown-shcet of the generator B'by a space, which is filled withplaster of, Paris or other suitable non-conductor,

It should be supplied with water, which occupies one-third or more of its interior capacity asiindicuted in the drawing. The eflice of this secondary generator is to furnish a're ceptacle for all the hot gases from the furnace after they have been combined with gases of decomposed steam, as hitherto shown, and afidrd opportunity and. means for such gases to pass through a body-of water, whereby they impart thcirheat to snchwat er and convert it into steam. At the same time, a volume of direct steam from the prirnury-generatoris'admitted, for the double purposeofforeing in the gaseous products, and of adding its quantum of heat to the temperature of them'at'er,

The'products of combustion mixed with steer 11,115 indicatedby the redwand blue arrows, enter the whter in the secondary gencratonas shown in the drawing, and, by their high temperature,- develope a portion of suchfwater in the secondary generator into steami They are compelled to passthrough th'ej-body of thc'water in the gem crater by means of the deflector-plates o and o, as indicateclk- I Y In future, the course of the steam-and gaseous products will bc representcd' bythrce arrows colored red, blue, and black, respectively. V I v p I The effect of the water in the secondary generator is to wash: the hcav ier'impurities from the 'gasesnf combustion, which impurities naturally settle upon the conical surface of the bottom of the g en'era tor', suitable proyisionbcing made for their removal by blow-off cocks p. l V v, I p

The combination of steam and gaseous forces rising from the aurfaceof'the water in the secondary generator, proceeds tofindan outlet through the contracted nozzle q, within the enclosed chamber- 1', and which, like the outlets before described, may be! arranged so that steamfromthe primary generator maybe admitted through" the pipe 8 branching from the pipe G, to eifectth'o some oflice,,as before described; Ihe'accumul'ated motive-- agents, which the apparatus fabove,described-developers, are now colle g dg 'flii ntho-inhaler chamber. acetate location, as shown, is directly above the secondary "mentor, and from then'cethey can beaconducted through 9 a proper dclirerypipe', N, to beemployed in driving an engine, or for heatmgor othorpurposos,

It will be observed that means is provided,: throug'h the'fpipe O of introducing steam from he primary generator over the fire, andthfus' supply oxygen thereto when eman tes nlso, by means of the pipe Roombined steam and gaseous products of the snme'quality as those entering the secondary generator maybe dis.-

charged into' the side pipo H, and bylitbe distributed agein throughitlie, diiferent channels which lead from'ih- Having thus described the a'pparatusshown in the drawings, itwill beseen that. its leading charaoteristib i consists, first, in introducing into engines of this class a secondary generator, into the water in which the gasesof thefurnace are forced by the superior pressure of steam iathe primarygenerator, and are made toact upon y it tog generate more steam,

"relieving the furnace frompre'ssure, whenever desired, by the agency of the 'steam developed by the primary generator; a a I I wish it to be understood that I doriot, confine myself to, the form of'the apparatus or 0 its several parts, as shawmnbr to the particular described arrangement of the furnace with the generators; neither-do I innit while, in turn, thcse gases, are purifiedbythe action of the water; and second, in

myself to a single secondary generator, as it is evident that, without change of principle, more than one such secondary generator can be employed, and the product of each be transferred, by'e repetition ot the means shown, to the next succession.

"What I-claim us, my invention, and desire tosecure by Letters Patent, is-

1. An apparatus for genereting steam, and'mixing and superheating air and steam, consisting of a furnace, C, a primary generator, B,- cnneeteti' with suclr furnace by suitable injection-pipes H, end. dischargo nozzles n n, and one or more secondary generators, E, arranged and operating together substnntielly as set forth.

2. I also claim connecting the furnace C with the passages; K, leading to the secondary generator E, by means ofthe blast-nozzle n, discharging steam from the primary generator, contents of the due D,for the passage of gases, and thereby relieving the furnace from pressure, as set forth.

3. I also cleim combining the conducting-passage or passages, K, leading to the secondary generutor, with the furnace G, by meansof suitable connecting-pipes, whereby the products of combustion, in the state in which the same ar in the passage K, can he readmitted to the fire-chamber, substantially-as described.

0. M. STILLMAN.

Witnesses J om: D. "Tnnnsmon, G. L. 'PENDLETON.

for the purpose of exhausting the p 

